BACKGROUND: Guidelines recommend long-term treatment for opioid use disorder including the use of buprenorphine; however, little is known about patients in long-term treatment. OBJECTIVE: Examine the prevalence and patient characteristics associated with long-term treatment retention (≥1 year) in an Office Based Opioid Treatment (OBOT) program with buprenorphine. Study Design: This is a 12-year retrospective cohort study of adults on buprenorphine in OBOT in a large urban safety-net primary care practice. METHODS: The primary outcome was retention in OBOT for ≥1 continuous year. Patients who re-enrolled multiple times in the program contributed repeated observations. Potential predictors of ≥1 year retention assessed were: age, race/ethnicity, psychiatric diagnoses, hepatitis C, employment, prior buprenorphine, ever heroin use, current cocaine, benzodiazepine and alcohol use on enrollment. Factors associated with ≥1 year OBOT retention were identified using generalized estimating equation logistic regression models. The different reasons for clinic disengagement by retention status (i.e. ≥1 year vs. <1 year) were also described. RESULTS: OBOT treatment periods (n=1605) among 1237 patients were assessed. Almost half, 44.7% (717/1605), of all treatment periods were ≥1 year and a majority, 53.7% (664/1237), of patients had at least one ≥ 1 year period. In adjusted analyses, female gender (Adjusted Odds Ratio [AOR] 1.55, 95% CI [1.20, 2.00]) psychiatric diagnosis (AOR 1.75 [1.35, 2.27]) and age (AOR 1.19 per 10 year increase [1.05, 1.34]) were associated with greater odds of ≥1 year retention. Unemployment (AOR 0.72 [0.56, 0.92]), Hepatitis C (AOR 0.59 [0.45, 0.76]), black race/ethnicity (AOR 0.53 [0.36, 0.78]) and Hispanic race/ethnicity (AOR 0.66 [0.48, 0.92]), compared to white, were associated with lower odds of ≥1 year retention. Relapse to substance use appeared to be a less common reason for disengagement for the ≥1 year (23.3%) compared to the <1 year (40.1%) treatment periods. CONCLUSIONS: Over half of patients were successfully retained in Office Based Opioid Treatment with buprenorphine for ≥1 year. However, significant disparities in one-year treatment retention were seen, including poorer retention for patients who were younger, black, Hispanic, unemployed, or with hepatitis C. / 2018-11-09T00:00:00Z